1. Field of Invention
The present invention relates to a solar fluid heater, which performs the functions of absorbing solar energy, converting it to heat and transferring this heat to a working fluid with a minimum of heat loss. More specifically, the present invention relates to a solar fluid heater which maximizes the utilization of solar radiation focused on or near the center line of a transparent pipe containing a fluid to be heated.
2. Description of Prior Art
Heretofore numerous efforts have been made to utilize solar energy for heating fluids. However, these prior art devices in their overall design have not achieved the heat transfer efficiency required to make them practical or effective for commercial utilization.
One type of prior art solar fluid heater device is disclosed in U.S. Pat. No. 1,575,309 to Anderson. In this device the efficiency of heat transfer is somewhat enhanced by use of heat transfer baffles disposed within a fluid conveying pipe and extending longitudinally thereof. However, the Anderson water heater suffers from the disadvantage that a large portion of incident solar energy is lost within the pipe assembly because no attempt is made to internally focus solar radiation on the heat transfer baffles. Therefore, the radiation entering the pipe assembly must be very accurately focused onto said assembly to maximize the efficiency of the device.
Another type of solar fluid heater is disclosed in U.S. Pat. No. 1,661,473 to Goddard et al. The Goddard device makes use of multiple reflections of solar radiation within the heater assembly to concentrate the radiation. However, there is still a considerable amount of energy lost in the Goddard device since all of the radiation incident on the reflectors is not directly transferable to the fluid being heated.
Still another type of prior art solar fluid heater is disclosed in U.S. Pat. No. 2,969,788. Newton utilizes a plurality of reflectors to concentrate incident solar radiation on fluid conduits. However, as in the Goddard device, a substantial amount of incident solar energy, which is absorbed by the reflectors, is never transferred to the fluid to be heated.